The service of a traditional optical network is scheduled in a static configuration mode through network management, and a dynamic activation mode is not supported. At the same time, most of the traditional optical networks employ linear and ring networking technologies, and use multiplex section protection and sub-network connection protection in protective recovery, which is basically a static recovery method. However, with the rapid development of data service and private line service, demand for network bandwidth is becoming stronger, and requirements on the dynamic allocation of network bandwidth is also becoming more urgent. The network is required to have dynamic activation capacity and to support the structure of mesh networks, and also have flexible extension capacity and a function of rapid protective recovery. Automatic Switch Optical Network (ASON) resolves the above problem. ASON uses GMPLS (Generalized Multiprotocol Label Switching) Protocol on the control plane, which has become a critical technology in the development of the optical network. In ASON, two new connection types are provided: one is a soft permanent connection mode and the other is a switched connection mode. At present, the ITU-T (International Telecommunication Union Telecommunication Standardization Sector) has basically completed the architecture and definitions of various requirements of ASON, and the IETF (Internet Engineering Task Force) has completed protocol extension and definitions of intra-single domain signaling, automatic discovery and routing.
With the development of the ASON network, the problem of managing of large-scale network needs to be solved in the control plane. At present, both the ITU-T and the OIF (Optical Internet Forum) use a hierarchical network model in which a control domain of the lower layer is represented by a proxy node in the upper layer, and the proxy node may issue the abstract topology, inter-domain link, accessible address and thereby represent the domain. Therefore, a hierarchical network may be formed upwardly layer by layer. For example, in FIG. 1, Layer 0 is an actual network which is divided into a plurality of control domains, such as CD1, CD2, CD3 and CD4, and on Layer 1, each domain is abstracted as a node, i.e. RC11, RC12, RC13 and RC14 and so on in the figure. The whole network has a network topology of three layers.
In a multi-domain network, the speed of connection recovery becomes an important bottleneck, because in the case of the multi-domain network, the connection passes through a plurality of domains and the number of nodes that are passed is much greater than that in the case of a single domain network. This has become an urgent problem that needs to be solved after completion of network extension. Usually, for cross-domain connection service, when an intra-domain failure occurs, an intra-domain tunnel is employed to implement local recovery. When a failure occurs on an inter-domain link, an inter-domain protection or rapid recovery mechanism is usually employed to recover from the failure. However, an end-to-end connection recovery needs to be performed when the intra-domain cannot be recovered from a failure due to insufficient intra-domain bandwidth resources, or when the inter-domain rapid recovery mechanism is disabled or there is no related inter-domain rapid recovery method if an inter-domain failure occurs. However, a cross-domain connection is required to signal via External Node-Node Interface (ENNI), and session process needs to be established in segments during establishment of the connection. Because the whole end-to-end cross-domain connection service of the cross-domain connection service cannot be specifically determined, the failure detecting node cannot report, to the first node of the service, information concerning the cross-domain connection service in which the failure occurs. Therefore, the end-to-end connection recovery of the cross-domain connection service is hard to perform, and the viability of the cross-domain connection service is lowered.